iftop – network traffic

iftop

– display bandwidth usage on an interface by host. iftop listens to network traffic on a named interface, or on the first interface it can find which looks like an external interface if none is
specified, and displays a table of current bandwidth usage by pairs of hosts. iftop must be run with sufficient permissions to monitor all net-
work traffic on the interface for more information, but on most systems this means that it must be run as root.